Bisacodyl (Dulcolax) suppositories are stimulant laxatives that work in less than one hour. Bisacodyl is typically prescribed for relief of constipation and for the management of neurogenic bowel dysfunction as well as part of bowel preparation before medical examinations, such as for a colonoscopy. Bisacodyl is a diphenylmethane derivative and was first used as a laxative in 1953 due to its similarity to phenolphthalein. Bisacodyl works by stimulating enteric nerves to cause colonic mass movements. It is also a contact laxative; it increases fluid and NaCl secretion. SUPPOSITORIES, 10 MG.